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Future volcanic activity at Clear Lake

The complex eruptive history over the past 2 million years and the Holocene age of the youngest eruptions indicate that the Clear Lake magmatic system is not extinct and that future eruptions are possible.

Although future eruptions are possible in the Clear Lake field, predicting their timing is difficult. From radiocarbon dates and numbers of ash beds beneath Clear Lake, we know that the youngest eruptions happened sometime around 8,500 years ago. However, this is a brief period in geological terms. Based on the past patterns of volcanic activity in the field, where eruptions have occurred for periods of about 300,000 years, the current episode (which began about 100,000 years ago) could be in an early stage and may continue for another 200,000 years.

Phreatomagmatic eruption column rising from the east Ukinrek Maar crater, Alaska. This is the most recent eruption type to have occurred in the Clear Lake Volcanic Field, about 8,500 years ago.

The most likely type of eruption which could occur in the Clear Lake Volcanic Field is either a phreatomagmatic eruption close to or beneath Clear Lake, or a scoria cone eruption northeast of Clear Lake, especially around the east arm of the lake. Phreatomagmatic eruptions are explosive, and would pose ballistic, ash-fall, and wave hazards to the lakeshore and ash-fall hazards to areas within a few kilometers of the vent. Eruptions away from the lake could produce scoria and ash fall and lava flows, and would pose hazards within a few kilometers of the vents. 

Such a long period of multiple volcanic events, the presence of a possible area of partial melt (5-10%) beneath both Clear Lake and The Geysers, and the numerous springs and gas vents in the region, suggest that the Clear Lake system is still active and could be for quite some time. However, ongoing research, particularly geophysical surveys and detailed studies of the field's eruption history, will shed more light on its evolution and potential future eruptions.